Heating system



P 1939- R. L. CAMPBELL 2,155,890

HEATING SYSTEM Filed Jan. 15, 1936 INVENTOR W A. Wee BY M ATTORNEY l atemed Apr, 25. 1939 UNITED STATES PATENT OFFICE signor to Detroit Lubricator Mich, a corporation of Michigan Company, Iletroit,

Application January l5, 1938, Serial No. 59,176

1 Claim.

My invention relates generally to heating systems and more particularly to control systems therefor.

One of the objects of my invention is to pro- 5. vide aheating system having a new and improved control system for controlling the operation thereof and to prevent overheating of the boiler of the heating system.

Another object of my invention is to provide a simple and inexpensive control system for a heating apparatus and of a character such that overheating of the boiler is prevented.

The drawing shows a diagrammatic view of a heating system embodying my invention. 4

Referring to the drawing by characters of reierence there is shown a hot water heating system including a boiler I in which water may be heated by a heating means including a fuel stoker operated by an electric motor 2. Any other suitable heat supplying means, such as an oil burner or gas burner, may be employed if desired. Leading out oi the boiler I and preferably from the'top thereof is an outlet or feed pipe 3 through which the hot water is supplied to the heat exchange, or transfer means or radiators (not shown) in a room or other enclosed space to be heated. A suitable check valve 4 is preferably provided and located in the feed line or riser pipe 3 to prevent back dew and circulation of the water by gravity.

Connected into and through the side wall 01' the boiler I there is a return pipe I through which the heating fluid or water returns to the boiler I from the radiators. In the return pipe 5 there is a pump means or water circulator I which is preferably located adjacent the boiler I, as shown. The water circulator I may be of any suitable type and is operated by an electric motor which, in the present instance, is enclosed in a casing I and mounted on the upper end of the circulator i.

In the room or other enclosed space, the air of which is to be heated, there is a thermostat, designated in general by the numeral 2, and which may be of any suitable type. The thermostat diagrammatically shown in the drawing includes a fixedcontact 9 engageable with a contact II carried by an arm I I of bi-metal, or other material movable in response to changes in ambient temperature of the air or any other medium to be heated. The fixed contact I of the room thermostat 8 is connected to a main lead wire I2, and the other or movable contact II is connected by a lead wire it to one terminal of the electric motor which drives the water circulater 6. The other terminal of the circulator motor is connected to the other main lead wire, designated at I l, by means of a lead wire IS. The circulator motor and room thermostat are thus in series circuit.

A control device, designated in general by the numeral I8, is provided for also controlling the operation of the water circulator Ii. The control device I6 is preferably mounted on the top" of the boiler i and is preferably of the type which 10 is operable in response to boiler temperature. The control device I8, as shown diagrammatically, has a contact I1 and a movable arm I8 which is adapted to engage contact II at a predetermined boiler temperature. The contact I1 is connected u to the lead line I3, which connects the room thermostat and circulator motor, by a lead wire IO, and the arm I I is connected by a lead wire I! to the lead wire which connects the contact 0 of the room thermostat II to the main line I2. Thus the control device It and the room thermostat l are in shunt circuit and either is adapted to control operation of the water circulator without the aid of the other.

Theelectric motor 2 of the fuel stoker is in a circuit which includes a control device, designated in general by the numeral 20. The control device 20, like the control device I6, is preferably mounted on the top of the boiler I and is preferably of the type which is operable in response to boiler temperature. as diagrammatically shown, includes a contact 2i engageable by a movable arm 22 at a predetermined boiler temperature for which the device is set to operate. A lead wire 23 connects the contact 2| and one terminal of the electric motor 2, while the arm 22 is connected to a main line 24 by a lead wire 25. The other terminal of the electric motor 2 is connected by a lead wire 21 to the other main lead wire, indicated at 28.

The operation of the herein described heating system is as follows: The control device 20 may be set to operate at a predetermined desired low temperature of the boiler,'say F'., to close the circuit to the motor 2 of the fuel stoker, and may be set to operate and open the circuit thereto at say F. boiler temperature. This difierential in operation of the control device may be selected as desired, but a temperature dinerential in operation of from 5 F. to 8 F. is preferable. When the control device 20 is set, as above mentioned, the arm 22 will engage the contact 2i when the temperature of the boiler decreases to 170 F., and circuit will be completed to the stoker motor 2 from main line 24,

The control device 20,,

lead line 2!, switch arm n, lead line II to the motor 2 and from the motor 2 to the main line 28 by connecting lead wire 21. Additional heat will then be supplied to the water in the boiler and when the temperature of the water rises to 175 F., the control device will operate to stop operation of the stoker. The room thermostat I may be set to maintains. desired, substantially constant room temperature and when the thermostat becomes unsatisfied it closes circuit to the water circulator 6 which operates to supply hot water from the boiler to the radiator. The operation of the water circulator causes-a reducwhich results in to close circuit to thasto same. If the room thermostat I becomes satisfled during the operating period of the stoker, or shortly thereafter, the closing of the check valve restricts or stops circulation and the boiler water temperature is increased due to the fuel carry-over in the the box. Control device I! is set to operate to make contact, at a predetermined boiler temperature higher than the temperature at which the control device 20 operates to stop the stoker motor, or 175 1'2, and which temperature may be taken, ior purposes of exposition, as 200 1?. When the temperature of the water in the boiler reaches this high temperature the control device It will close the circuit to the circulator motor irrespective of the operation of the room thermostat, since the room thermostat and control device ii are in shunt circuit. Preferably the control device It is set to have a temperature differential of operation from 8 F. to 10 F. so that it will close circuit to desire to secure by Letters States is:

In a hot water heating system, a hot water boiler, a mechanical fuel stoker for heating the water in said boiler. ieed line and a return line connected to said boiler for circulation of the water through a hot water radiating system for heating a closed space, a valve closed against flow of water by natural convection through the radiating system, electrically operated pump means operable to circulate the water through said boiler and to open said valve and discharge the water to the radiating system, thermostatic means sensitive to the temperature of the closed space and operable to control said pump means irrespective of the temperature of the boiler water, temperature means sensitive to the temperature of the water in said boiler and operable upon a predetermined high temperature of the water in said boiler to start said pump means and upon a predetermined low temperature to stop said pump means independently of said thermostatic means, and means operable to maintain the water in said boiler at a temperature sufliciently high for immediate supply to the radiating system upon operation of said thermostatic means to start said pump means.

RICHARD L. CAMPBELL. 

